 /*******************************************************************************
  * Copyright (c) 2007 IBM Corporation and others.
  * All rights reserved. This program and the accompanying materials
  * are made available under the terms of the Eclipse Public License v1.0
  * which accompanies this distribution, and is available at
  * http://www.eclipse.org/legal/epl-v10.html
  *
  * Contributors:
  * IBM Corporation - initial API and implementation
  ******************************************************************************/

 package org.eclipse.ui.internal;

 import org.eclipse.core.commands.Command;
 import org.eclipse.core.commands.ParameterizedCommand;
 import org.eclipse.swt.SWT;
 import org.eclipse.swt.widgets.Table;
 import org.eclipse.swt.widgets.TableItem;
 import org.eclipse.ui.IPerspectiveDescriptor;
 import org.eclipse.ui.commands.ICommandService;
 import org.eclipse.ui.model.PerspectiveLabelProvider;

 /**
  * This handler is used to switch between perspectives using the keyboard.
  * <p>
  * Replacement for CyclePerspectiveAction
  * </p>
  *
  * @since 3.3
  */
 public class CyclePerspectiveHandler extends CycleBaseHandler {
     private PerspectiveLabelProvider labelProvider = new PerspectiveLabelProvider(
             false);
     
     /* (non-Javadoc)
      * @see org.eclipse.ui.internal.CycleBaseHandler#addItems(org.eclipse.swt.widgets.Table, org.eclipse.ui.internal.WorkbenchPage)
      */
     protected void addItems(Table table, WorkbenchPage page) {
         IPerspectiveDescriptor perspectives[] = page.getSortedPerspectives();
         for (int i = perspectives.length - 1; i >= 0; i--) {
             TableItem item = new TableItem(table, SWT.NONE);
             IPerspectiveDescriptor desc = perspectives[i];
             String text = labelProvider.getText(desc);
             if(text == null) {
                 text = "";//$NON-NLS-1$
 }
             item.setText(text);
             item.setImage(labelProvider.getImage(desc));
             item.setData(desc);
         }

     }

     /* (non-Javadoc)
      * @see org.eclipse.ui.internal.CycleBaseHandler#getBackwardCommand()
      */
     protected ParameterizedCommand getBackwardCommand() {
         final ICommandService commandService = (ICommandService) window.getWorkbench().getService(ICommandService.class);
         final Command command = commandService.getCommand("org.eclipse.ui.window.previousPerspective"); //$NON-NLS-1$
 ParameterizedCommand commandBack = new ParameterizedCommand(command, null);
         return commandBack;
     }

     /* (non-Javadoc)
      * @see org.eclipse.ui.internal.CycleBaseHandler#getForwardCommand()
      */
     protected ParameterizedCommand getForwardCommand() {
         final ICommandService commandService = (ICommandService) window.getWorkbench().getService(ICommandService.class);
         final Command command = commandService.getCommand("org.eclipse.ui.window.nextPerspective"); //$NON-NLS-1$
 ParameterizedCommand commandF = new ParameterizedCommand(command, null);
         return commandF;
     }

     /* (non-Javadoc)
      * @see org.eclipse.ui.internal.CycleBaseHandler#getTableHeader()
      */
     protected String getTableHeader() {
         return WorkbenchMessages.CyclePerspectiveAction_header;
     }

     /* (non-Javadoc)
      * @see org.eclipse.core.commands.AbstractHandler#dispose()
      */
     public void dispose() {
         if (labelProvider!=null) {
             labelProvider.dispose();
             labelProvider = null;
         }
         super.dispose();
     }
 }

